Growing local datastore from command line

I've run into an issue where I need to increase the size of a datastore, but I do not see the Extent Device when trying to do so. A few KB articles have lead me to believe that this is an issue when esxi is installed on the same virtual disk as the datastore.

Using the article below, I've gotten to the point where I'm ready to run the following command.

http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&docTypeID=DT_KB_1_1&externalId=2002461

# partedUtil resize "/vmfs/devices/disks/naa.6842b2b07402500014a6272f0727217a" 3 10229760 2339373055

Another kb has informed that there shouldn't be any disk i/o going on when this command is run, so my first step would be to power down the VMs on the host. Is this correct/necessary?

My main question is, what are the dangers of running this command? If there is an error, can I just roll back to the previous sector count?

Is there a potential for data loss?

Thanks in advance.